Progressive ovarian carcinoma induces synthesis of type I and type III procollagens in the tumor tissue and peritoneal cavity.

Increased serum concentrations of aminoterminal propeptide of type III procollagen occur in advanced ovarian cancer. To study their origin, we compared the expressions of type I and type III procollagens in ovarian tumor tissue and the peritoneal cavity with immunoassays for the propeptide domains of these procollagens. Samples of tumor cyst fluid, peritoneal ascitic fluid, tumor vein blood, and peripheral blood were obtained at operation from 50 women with malignant ovarian neoplasms and 61 women with benign neoplasms. The ascitic fluid concentrations of both type I and type III procollagen antigens were significantly higher in the malignant tumors than in the benign ones, but this difference was evident only for type I procollagen in the tumor cysts. The aminoterminal propeptide of type III procollagen concentration in the peripheral blood was higher in the patients with malignant tumors, whereas the concentrations were similar in the tumor veins. The enhanced type I procollagen synthesis in the malignant tumors did not affect the corresponding antigen in the blood. The findings suggest that progressive ovarian carcinoma invariably induces a fibroproliferative response, characterized by active expression of type I and type III procollagens. The increased circulating aminoterminal propeptide of type III procollagen is derived from the peritoneal cavity rather than from the tumor tissue via the ovarian vein.

The brain at high altitude: hypometabolism as a defense against chronic hypoxia?

The brain of hypoxia-tolerant vertebrates is known to survive extreme limitations of oxygen in part because of very low rates of energy production and utilization. To assess if similar adaptations may be involved in humans during hypoxia adaptation over generational time, volunteer Quechua natives, indigenous to the high Andes between about 3,700 and 4,900 m altitude, served as subjects in positron emission tomographic measurements of brain regional glucose metabolic rates. Two metabolic states were analyzed: (a) the presumed normal (high altitude-adapted) state monitored as soon as possible after leaving the Andes and (b) the deacclimated state monitored after 3 weeks at low altitudes. Proton nuclear magnetic resonance spectroscopy studies of the Quechua brain found normal spectra, with no indication of any unusual lactate accumulation; in contrast, in hypoxia-tolerant species, a relatively large fraction of the glucose taken up by the brain is released as lactate. Positron emission tomographic measurements of [18F]2-deoxy-2-fluoro-D-glucose (FDG) uptake rates, quantified in 26 regions of the brain, indicated systematically lower region-by-region glucose metabolic rates in Quechuas than in lowlanders. The metabolic reductions were least pronounced in primitive brain structures (e.g., cerebellum) and most pronounced in regions classically associated with higher cortical functions (e.g., frontal cortex). These differences between Quechuas with lifetime exposure to hypobaric hypoxia and lowlanders, which seem to be expressed to some degree in most brain regions examined, may be the result of a defense adaptation against chronic hypoxia.

Differential processing of type I and type III procollagens in the tumour cysts and peritoneal ascitic fluid of patients with benign and malignant ovarian tumours.

Progressive ovarian carcinoma induces the synthesis of type I and type III procollagens both in the tumour tissue and in the peritoneal cavity. We studied the processing of these proteins by determining the different antigen forms related to their propeptide parts by gel filtration and subsequent immunological assays. Samples of ovarian cyst fluid and peritoneal ascitic fluid were obtained from patients with benign and malignant ovarian tumours. In both benign and malignant ovarian cysts, the predominant procollagen antigens were the free propeptides, with few or no larger components, indicating efficient processing of types I and III procollagens in the tumour tissue. In ascitic fluid the processing was more variable. The aminoterminus of type III procollagen was partially unprocessed in all samples studied, whereas that of type I procollagen was nearly always completely processed. There was a clear difference between malignant and benign tumours in the processing of the carboxyterminus of type I procollagen: a significant part of the carboxyterminal propeptide antigen was invariably associated with a collagenous domain in malignant tumours, whereas in benign tumours the free propeptide predominanted. The results indicate that interstitial procollagens are effectively processed in the tumour tissue during the fibroproliferative reaction typical of malignant ovarian tumours, whereas the processing of the procollagens released into peritoneal ascitic fluid is incomplete.

Aminoterminal propeptide of type III procollagen in ovarian cancer. A review.

The concentration of the aminoterminal propeptide of type III procollagen (PIIINP) in serum is a measure of the activity of the metabolism of type III collagen, which is a major constituent of soft connective tissues and of the connective tissue stroma of solid tumours. In advanced ovarian carcinoma, serum PIIINP serves as a tumour-associated antigen, its changes reflecting and preceding changes in the clinical behaviour of the malignancy. Elevated values of serum PIIINP are also observed in endometrial and cervical malignancies, though less frequently than in ovarian tumours. Very high concentrations of PIIINP are found in ovarian carcinoma ascites, suggesting an ongoing fibro-proliferative reaction in the peritoneal cavity as a response to the tumour.

Immunohistochemical study of type I collagen and type I pN-collagen in benign and malignant ovarian neoplasms.

BACKGROUND: Type I collagen is a major constituent of the interstitial connective tissue. Although ovarian carcinoma is known to induce the expression of type I collagen in the peritoneal cavity, the distribution and metabolic activity of this collagen in ovarian tumor tissue are not known. METHODS: The distributions and staining intensities of different molecular forms of type I collagen in ovarian neoplasms were studied immunohistochemically with antibodies to the aminoterminal propeptide of type I procollagen (PINP) and the cross-linked carboxyterminal telopeptide of type I collagen (ICTP), reflecting the presence of newly synthesized and old, cross-linked type I collagen, respectively. RESULTS: A regular pattern of moderately staining, relatively uniform fibers was observed in the stroma of benign serous and mucinous cystadenomas, indicating limited participation in tumor growth. The staining was accentuated subepithelially in borderline epithelial neoplasms and in well differentiated cystadenocarcinomas, suggesting induction of the stromal collagen synthesis by the tumor cells. Fewer degraded collagen fibers were found in moderately differentiated carcinomas, most likely because of enzymatic degradation of the stroma surrounding the neoplasms during tumor spread. Strongly staining, irregular collagen fibers occurred closely around islets of tumor cells in undifferentiated malignant neoplasms and in metastases of ovarian carcinomas; also, intracellular staining was present in part of the malignant cells. In most cases, the staining reactions obtained with the two different antibodies were similar, probably indicating rapid processing of the newly synthesized type I collagen (indicated by PINP) to a maturely cross-linked form (indicated by ICTP). CONCLUSIONS: Synthetic and degradative processes are typical of the collagenous matrix in malignant ovarian tumors. Aberrant expression of type I collagen may occur in anaplastic ovarian carcinomas.

Organization of type III collagen in benign and malignant ovarian tumors. An immunohistochemical study.

BACKGROUND: Abnormal interaction with the extracellular matrix is a basic property of malignant cells. Type III collagen is a major constituent of the extracellular matrix of soft tissues. METHODS: Deposition of the aminoterminal propeptide of type III procollagen (PIIINP) was studied in benign (n = 41), borderline (n = 4), and malignant (n = 32) human ovarian tumors using the avidin-biotin-immunoperoxidase technique and affinity-purified antibodies to human PIIINP: It was then compared with the serum PIIINP concentrations of the patients at the time of operation. RESULTS: In malignant tumors, the distribution of PIIINP was irregular both close to the epithelial cancer cells and further away, in the stroma. Another feature typical of malignant tumors was the varying staining intensity of the PIIINP-positive fibers. The benign tumors were characterized by a regular organization and an intensive staining of PIIINP: Borderline tumors showed a slightly decreased staining intensity and altered PIIINP distribution. A significant positive correlation was found between the PIIINP concentration in serum and the degree of irregularity in the distribution of PIIINP: CONCLUSIONS: These preliminary results indicate that malignant transformation in ovarian tumors is associated with disintegration of adjacent collagenous structures and with alterations in type III procollagen metabolism, which also leads to increased serum PIIINP levels. They suggest that biochemical or immunohistochemical detection of the PIIINP antigen could be clinically useful in ovarian tumors.